U.S. patent number 5,952,093 [Application Number 08/803,566] was granted by the patent office on 1999-09-14 for polymer composite comprising a inorganic layered material and a polymer matrix and a method for its preparation.
This patent grant is currently assigned to The Dow Chemical Company. Invention is credited to Chai-Jing Chou, Kevin L. Nichols.
United States Patent |
5,952,093 |
Nichols , et al. |
September 14, 1999 |
**Please see images for:
( Certificate of Correction ) ** |
Polymer composite comprising a inorganic layered material and a
polymer matrix and a method for its preparation
Abstract
A polymer composite comprises a polymer matrix having, dispersed
therein, layers of an inorganic material derived from a
multilayered inorganic material such as clay intercalated with an
inorganic intercalant. The multilayered inorganic material may also
be intercalated with an organic material.
Inventors: |
Nichols; Kevin L. (Midland,
MI), Chou; Chai-Jing (Missouri City, TX) |
Assignee: |
The Dow Chemical Company
(Midland, MI)
|
Family
ID: |
25186867 |
Appl.
No.: |
08/803,566 |
Filed: |
February 20, 1997 |
Current U.S.
Class: |
428/323; 428/328;
428/423.1; 428/702; 428/331; 428/425.9; 428/407; 428/704; 428/696;
428/689 |
Current CPC
Class: |
B32B
5/04 (20130101); B32B 19/02 (20130101); Y10T
428/31609 (20150401); Y10T 428/2998 (20150115); Y10T
428/259 (20150115); Y10T 428/31551 (20150401); Y10T
428/256 (20150115); Y10T 428/25 (20150115) |
Current International
Class: |
B32B
19/02 (20060101); B32B 19/00 (20060101); B32B
5/04 (20060101); B32B 005/16 () |
Field of
Search: |
;428/402,403,407,323,331,328,689,696,702,704 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 352 042 |
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Jan 1990 |
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EP |
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0 358 415 |
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Mar 1990 |
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EP |
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0 398 551 |
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Nov 1990 |
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EP |
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93/04117 |
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1993 |
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WO |
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93/04118 |
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1993 |
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WO |
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93/11190 |
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1993 |
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WO |
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95/06090 |
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1995 |
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WO |
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Other References
Abstract of J51109998-A (Sep. 1976). .
Abstract of J02208358-A (Aug. 1990). .
Vaia et al., "Interlayer Structure and Molecular Environment of
Alkylammonium Layered Silicates", Chem. Mater., 1994, 6, pp.
1017-1022. .
Kurauchi et al., "Nylon 6-Clay Hybrid-Synthesis, Properties and
Application to automotive Timing Belt Cover," SAE Technical Paper
Series, 910584. (1991). .
Sumitomo Corporation, Sumitomo Corp. to Build New Firm For Fine
Chemicals In U.S., Jun. 15, 1989, p. 7. .
Fukushima et al., "Synthesis of an Intercalated Compound of
Montmorillonite and 6-Polyamide," Journal of Inclusion Phenomena 5,
5 1987, pp. 473-482. .
Vaia et al., "Synthesis and Properties of Two-Dimensional
Nanostructures by Direct Intercalation of Polymer Melts in Layered
Silicates," Chem. Mater., vol. 5, No. 12, 1993. .
Fukushima, et al., "Swelling Behaviour of Montmorillonite By
Poly-6-Amide," Clay Minerals, 23, 1988, pp. 27-34..
|
Primary Examiner: Le; Hoa T.
Attorney, Agent or Firm: Shepherd; Philip D Zerull; Susan
M
Claims
What is claimed is:
1. A composite comprising a polymer matrix having, dispersed
therein, an inorganic layered material intercalated with an organic
intercalant and an ionic or non-ionic inorganic intercalant.
2. The composite of claim 1 wherein the polymer matrix is a
thermoset or thermoplastic polymer or a vulcanizable or
thermoplastic rubber.
3. The composite of claim 2 wherein the polymer matrix is a
thermoplastic polymer of a polymer or copolymer of ethylene,
propylene; a monovinylidene aromatic; a polycarbonate; or a
thermoplastic polyurethane or mixtures thereof.
4. The composite of claim 3 wherein the polymer matrix is a linear
low density polyethylene, a low density polyethylene or the
homogeneously branched linear and substantially linear ethylene
copolymers with a density of from about 0.85 to about 0.92
g/cm.sup.3 and a melt index from about 0.1 to about 10 g/min;
substantially linear, functionalized, ethylene copolymers.
5. The composite of claim 2 wherein the polymer matrix is a
thermoset resin.
6. The composite of claim 5 wherein the thermoset resin is a
thermoset phenolic resin; a thermoset epoxide or epoxy resin; a
thermoset polyester resin; a thermoset polyurethane; a thermoset
urea resin; melamine resin, furan resin, or vinyl ester resin.
7. The composite of claim 6 where in the thermoset resin is an
epoxy or urethane resin.
8. The composite of claim 1 wherein the inorganic layered material
is a phyllosilicate; an illite mineral, a layered double hydroxide
or mixed metal hydroxide, ReCl.sub.3 and FeOCl; TiS.sub.2,
MoS.sub.2, MoS.sub.3 ; Ni(CN).sub.2 ; H.sub.2 Si.sub.2 O.sub.5,
V.sub.5 O.sub.13, HTiNbO.sub.5, Cr0.5V0.5S.sub.2,
W0.2V.sub.2.8O.sub.7, Cr.sub.3 O.sub.8, MoO.sub.3 (OH).sub.2,
VOPO.sub.4 -2H.sub.2 O, CaPO.sub.4 CH.sub.3 --H.sub.2 O,
MnHAsO.sub.4 --H.sub.2 O, or Ag.sub.6 Mo.sub.10 O.sub.33 .
9. The composite of claim 8 wherein the inorganic layered material
is montmorillonite, nontronite, beidellite, volkonskoite,
hectorite, saponite, sauconite, magadiite, or kenyaite.
10. The composite of claim 8 wherein the inorganic layered material
is a phyllosilicate.
11. The composite of claim 1 wherein the inorganic intercalant is
an inorganic polymeric substance obtained by hydrolyzing a
polymerizable metallic alcoholate or a colloidal compound.
12. The composite of claim 11 wherein the inorganic intercalant is
a polymeric substance which is the hydrolyzed product of
Si(OR).sub.4, Al(OR).sub.3, Ge(OR).sub.4, Si(OC).sub.2
H.sub.5).sub.4, Si(OCH.sub.3).sub.4, Ge(OC.sub.3 H.sub.7),
Ge(OC.sub.2 H.sub.5).sub.4 or a mixture thereof.
13. The composite of claim 11 wherein the inorganic intercalant is
colloidal sized particle of the hydrolyzed form of SiO.sub.2,
Sb.sub.2 O.sub.3, Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, TiO.sub.2,
ZrO.sub.2 and SnO.sub.2 or a mixture thereof.
14. The composite of claim 13 wherein the inorganic intercalant has
a grain size of the colloidal inorganic is from about 5 to about
250 .ANG..
15. The composite of claim 11 wherein the inorganic intercalant is
modified at its surface by a cationic inorganic compound or a
metallic alcoholate different than the polymerizable metallic
alcoholate.
16. The composite of claim 15 wherein the cationic inorganic is a
metallic chloride; a metallic oxychloride, a nitrate chloride,
Ti(OC.sub.3 H.sub.7).sub.4, Zr(OC.sub.3 H.sub.7).sub.4,
PO(OCH.sub.3).sub.3, PO(OC.sub.2 H.sub.5).sub.3,
B(OCH.sub.3).sub.3, or B(OC.sub.2 H.sub.5).sub.3.
17. The composite of claim 1 wherein the organic intercalant is a
water-soluble polymer, a reactive organosilane, an ammonium,
phosphonium or sulfonium salt, an amphoteric surface active agent
or a chlorine compound.
18. The composite of claim 1 wherein the organic intercalant is
calcined.
19. A composite comprising a polymer matrix having, dispersed
therein, a layered inorganic filler intercalated with an organic
intercalant which is subsequently calcined or otherwise removed
from the layered inorganic filler.
20. The composite of claim 19 wherein the organic intercalant is a
water soluble polymer of vinyl alcohol; polyalkylene glycol; water
soluble cellulosic polymer; a polymer of an ethylenically
unsaturated carboxylic acid or its salt; polyvinyl pyrrolidone; a
quaternary ammonium salt; an amphoteric surface-active agent having
an aliphatic amine cationic moiety and a carboxyl, sulfate, sulfone
or phosphate anionic moiety; [HOCH.sub.2 CH.sub.2 N(CH.sub.3).sub.3
]+OH , C.sub.5 H.sub.4 ClNO, C.sub.5 H.sub.14 NOC.sub.4 H.sub.5
O.sub.6, C.sub.5 H.sub.14 NOC.sub.6 H.sub.7 O.sub.7, C.sub.5
H.sub.14 NOC.sub.6 H.sub.12 O.sub.7 ; or
where (-) is a covalent bond to the surface of the layered
material, m is 0, 1 or 2; n is 1, 2 or 3 with the proviso that the
sum of m and n is equal to 3; R.sup.1 is a nonhydrolyzable organic
radical and is not displaceable during the formation of the
composite; R is the same or different at each occurrence and is an
organic radical which is not hydrolyzable and displaceable during
the formation of the composite which is reactive with the polymer
matrix or at least one monomeric component of the polymer.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a composite comprising a polymer
and an inorganic additive, more specifically, layers of a swellable
material, and to a method for preparing the polymer composite.
Polymer composites comprising a polymer matrix having one or more
additives such as a particulate or fiber material dispersed
throughout the continuous polymer matrix are well known. The
additive is often added to enhance one or more properties of the
polymer.
Useful additives include inorganic layered materials such as talc,
clays and mica of micron size.
A number of techniques have been described for dispersing the
inorganic layered material into a polymer matrix. It has been
suggested to disperse individual layers, e.g., platelets, of the
layered inorganic material, throughout the polymer. However,
without some additional treatment, the polymer will not infiltrate
into the space between the layers of the additive sufficiently and
the layers of the layered inorganic material will not be
sufficiently uniformly dispersed in the polymer.
To provide a more uniform dispersion, as described in U.S. Pat. No.
4,889,885, sodium or potassium ions normally present in natural
forms of mica-type silicates and other multilayered particulate
materials are exchanged with organic cations (e.g., alkylammonium
ions or suitably functionalized organosilanes) thereby
intercalating the individual layers of the multilayered materials,
generally by ionic exchange of sodium or potassium ions. This
intercalation can render the normally hydrophilic mica-type
silicates organophilic and expand its interlayer distance.
Subsequently, the layered material (conventionally referred to as
"nanofillers") is mixed with a monomer and/or oligomer of the
polymer and the monomer or oligomer polymerized. The intercalated
silicate is described as having a layer thickness of 7 to 12 .ANG.
and an interlayer distance of 30 .ANG. or above.
In WO 93/11190, an alternative method for forming a composite is
described in which an intercalated layered, particulate material
having reactive organosilane compounds is dispersed in a
thermoplastic polymer or vulcanizable rubber.
Yet additional composites containing these so-called nanofillers
and/or their methods of preparation are described in U.S. Pat. Nos.
4,739,007; 4,618,528; 4,528,235; 4,874,728; 4,889,885; 4,810,734;
4,889,885; 4,810,734; and 5,385,776; German Patent 3808623;
Japanese Patent J02208358; European Patent applications 0,398,551;
0,358,415; 0,352,042; and 0,398,551; and J. Inclusion Phenomena 5,
(1987), 473 ?483; Clay Minerals, 23, (1988), 27; Polym. Preprints,
32 (April 1991), 65-66; Polym. Prints, 28, (August 1987), 447-448;
and Japan Kokai 76,109,998.
However, even with these numerous described composites and methods,
it still remains desirable to have an improved composite and method
for forming polymer composites derived from a multilayered additive
to make composites having improved properties over the polymer
alone.
SUMMARY OF THE INVENTION
Accordingly, in one aspect, the present invention is a composite
comprising a polymer matrix having, dispersed therein, delaminated
or exfoliated particles derived from a multilayered inorganic
material intercalated with an inorganic intercalant. Optionally, an
organic intercalant can also be employed. If employed, the
optionally employed organic intercalant can be calcined or at least
partially removed from the multilayered inorganic material.
In another aspect, the present invention is a composite comprising
a polymer matrix having dispersed therein delaminated or exfoliated
particles derived from a multilayered material which has been
intercalated with an organic intercalant only which is subsequently
calcined or otherwise at least partially removed from the layered,
reinforcing material.
In a third aspect, the present invention is a method for forming a
composite which method comprises contacting a polymer or a
precursor to the polymer with a multilayered inorganic particulate
material intercalated with an inorganic polymeric intercalant and,
optionally, an organic intercalant. If the optionally employed
organic intercalant is used, it can be calcined or at least
partially removed from the multilayered inorganic material prior to
mixing the material with the polymer.
In a preferred embodiment, the polymer is a melt processible,
thermoplastic polymer and the method comprises mixing the polymer
and intercalated material at conditions to disperse the
intercalated material into the polymer.
The polymeric compositions of this invention can exhibit an
excellent balance of properties and can exhibit one or more
superior properties such as improved heat or chemical resistance,
ignition resistance, superior resistance to diffusion of polar
liquids and of gases, yield strength in the presence of polar
solvents such as water, methanol, ethanol and the like, or enhanced
stiffness and dimensional stability, as compared to composites
which contain the same multilayered material which has not
previously been intercalated or where no intercalated material is
employed.
The composites of the present invention are useful in a wide
variety of applications including transportation (e.g., automotive
and aircraft) parts, electronics, business equipment such as
computer housings, building and construction materials, and
packaging materials.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the polymer matrix of the composite can
be essentially any normally solid polymer, including both thermoset
and thermoplastic polymers and vulcanizable and thermoplastic
rubbers.
A representative thermoplastic polymer which can be employed to
prepare the composites of the present invention is a thermoplastic
polyurethane such as derived from the reaction of a diisocyanate
such as 1,5-naphthalene diisocyanate,
3,3'-dimethyl-4,4'-diphenylmethane diisocyanate,
4,4'-diphenyliso-propylidene diisocyanate,
4,4'-diisocyanatodiphenylmethane and the like and linear long-chain
diol such as poly(tetramethylene adipate), poly(ethylene
succinate), polyether diol and the like.
Another representative thermoplastic polymer is a polycarbonate
such as prepared by the reaction of an aromatic polyol (e.g.,
resorcinol, catechol, hydroquinone, a dihydroxynaphthalene, a
dihydroxyanthracene, a bis(hydroxyaryl) fluorene, a
dihydroxyphenanthrene, a dihydroxybiphenyl; and a
bis(hydroxyphenyl) propane), more preferably an aromatic diol, with
a carbonate precursor (e.g., carbonic acid derivative, phosgene,
haloformate, or carbonate ester such as dimethyl carbonate or
diphenyl carbonate, poly(methane bis(4-phenyl) carbonate),
poly(1,1-ether bis(4-phenyl)carbonate), and the like.
Yet other representative examples include thermoplastic polymers
and copolymers derived from esters of ethylenically unsaturated
methacrylic or acrylic acid such as poly(methyl or ethyl)acrylate,
poly(methyl or ethyl)methacrylate, including copolymers of methyl
methacrylate and a monovinylidene aromatic such as styrene,
copolymers of ethylene and ethyl acrylate, methacrylated
butadiene-styrene copolymers and the like; polymers derived from
ethylenically unsaturated monomers such as polyolefins (e.g.,
polypropylene and polyethylene including high density polyethylene,
linear low density polyethylene, ultra low linear density
polyethylene, homogeneously branched, linear ethylene/
.alpha.-olefin copolymers, homogeneously branched, substantially
linear ethylene/ .alpha.-olefin polymers, and high pressure, free
radical polymerized ethylene copolymers such as ethylene-acrylic
acid (EAA) copolymers),highly branched low density polyethylene,
and ethylene-vinyl acetate (EVA) copolymers; polymers of
monovinylidene aromatics such as polystyrene and syndiotactic
polystyrene including copolymers thereof such as impact modified
polystyrene, styrene-ethylene copolymers, styrene-acrylonitrile
copolymers, acrylonitrile-butadiene-styrene copolymers and other
styrenic copolymers.
Still other representative examples of thermoplastic polymers
include polyesters such as poly(ethylene-1,5-naphthalate),
poly(1,4-cyclohexane dimethylene terephthalate), poly(ethylene
oxybenzoate), poly(para-hydroxy benzoate), polyethylene
terephthalate, polybutylene terephthalate and the like;
polysulfones such as the reaction product of the sodium salt of
2,2-bis(4-hydroxyphenyl) propane and 4,4'-dichlorodiphenyl sulfone;
polyetherimides; and polymers of ethylenically unsaturated nitriles
such as polyacrylonitrile; poly(epichlorohydrin); polyoxyalkylenes
such as poly(ethylene oxide); poly(furan); cellulose-based plastics
such as cellulose acetate, cellulose acetate butyrate; silicone
based plastics such as poly(dimethyl siloxane) and poly(dimethyl
siloxane co-phenylmethyl siloxane); polyether ether ketones;
polyamides such as poly(4-amino butyric acid), poly(hexamethylene
adipamide), poly(6-aminohexanoic acid), and poly(2,2,2-tri-methyl
hexamethylene terephthalamide); polylactones such as
poly(pivalolactone) and poly(caprolactone); poly(aryleno oxides)
such as poly(2,6-dimethyl-1,4-phenylene oxide); poly(arylene
sulfides) such as poly(phenylene sulfide); polyetherimides;
acetals; polyvinyl chloride; poly(vinylidene chloride) and the like
and blends of two or more of these polymers.
Preferred thermoplastic polymers include the polymers and
copolymers of ethylene and/or propylene, polymers and copolymers of
a monovinylidene aromatic compound, more preferably styrene,
polycarbonates, and thermoplastic polyurethanes or mixtures
thereof. Preferred ethylene polymers and copolymers include linear
low density polyethylenes, low density polyethylenes and the
homogeneously branched linear and substantially linear ethylene
copolymers with a density (ASTM D-792) of about 0.85 to about 0.92
g/cm.sup.3, more preferably of about 0.85 to about 0.90 0.92
g/cm.sup.3, and a measured melt index (ASTM D-1238 (190/2.16)) of
about 0.1 to about 10 g/min; substantially linear, functionalized,
ethylene copolymers, particularly a copolymer of ethylene with
vinyl acetate containing from about 0.5 to about 50 weight percent
units derived from vinyl acetate, are especially preferred,
especially copolymers of ethylene with vinyl acetate having a melt
index of about 0.1 to about 10 g/10 min; and copolymers of ethylene
with acrylic acid containing from about 0.5 to about 25 weight
percent units derived from acrylic acid.
Representative vulcanizable and thermoplastic rubbers which may be
useful in the practice of the present invention include rubbers
such as brominated butyl rubber, chlorinated butyl rubber,
polyurethane elastomers, fluoroelatomers, polyester elastomers,
butadiene/acrylonitrile elastomers, silicone elastomers, rubbers
derived from conjugated dienes such as poly(butadiene),
poly(2,3-dimethylbutadiene), poly(butadiene-pentadiene), and
poly(isobutylene), ethylene-propylene-diene terpolymer (EPDM)
rubbers and sulfonated EPDM rubbers, poly(chloroprene),
chlorosulphonated or chlorinated poly(ethylenes), and poly(sulfide)
elastomers. Other examples include block copolymers made up of
segments of glassy or crystalline blocks such as poly(styrene),
poly(vinyl-toluene), poly(t-butyl styrene), polyester and the like
and elastomeric blocks such as poly(butadiene), poly(isoprene),
ethylene-propylene copolymers, ethylene-butylene copolymers,
polyether ester and the like, e.g.,
poly(styrene)-poly(butadiene)-poly(styrene) block copolymers.
Thermoset resins differ from thermoplastic polymers in that they
become substantially infusible or insoluble irreversibly since they
are cured (cross-linked) as opposed to the thermoplastics which are
typically not cross-linkable and soften when exposed to heat and
are capable of returning to original conditions when cooled.
Representative examples of thermoset polymers which may be useful
in the practice of the present invention include thermoset phenolic
resins such as thermosettable resins containing resorcinol,
p-tertiary-octylphenol, cresol, alkylated phenolic novalac,
phenolic polyvinyl butyral, and phenolic cresol and an aldehyde
such as formaldehyde, acetaldehyde or furfural; thermoset polyimide
resins such as those curable resins based on pyromellitic
dianhydride, 3,3 ',4,4'-benzophenone-carboxylic dianhydride and
meta-phenylenediamine; thermoset epoxides or epoxy resins such as
the resins containing the reaction product bisphenol A or
derivatives thereof, e.g., the diglycidyl ether of bisphenol A, or
a polyol such as glycerol with epichlorohydrin and a cross-linking
or curing agent such as a polyfunctional amine, e.g.,
polyalkylenepolyamine; thermoset polyester resins such as the
reaction products of an unsaturated dicarboxylic acid such as
maleic or fumaric acid (which may be used in combination with a
saturated acid such as phthalic or adipic acid) with a dihydric
alcohol such as ethylene, propylene, diethylene and dipropylene
glycol which cure upon using an ethylenic unsaturated curing agent
such as styrene or diallyl phthalate, including thermosettable
allyl resins including resins derived from diallyl phthalates,
e.g., diallyl orthophthalate, diallyl isophthalate, diallyl
fumarates and diallyl maleates; thermoset polyurethanes including
those derived from the reaction of a diisocyanate, e.g., toluene
diisocyanate, methylene diphenyl diisocyanate, or isophorone
diisocyanate, or a polymeric isocyanate with a polyhydric alcohol
such as polypropylene glycol and, if required, an additional
cross-linking agent such as water; thermoset urea resins; melamine
resins, furan resins, and vinyl ester resins including epoxy
(meth)acrylates.
Of these polymers, the preferred thermoplastic polymers are
polycarbonates, homo- and copolymers of styrene, nylons,
polyesters, thermoplastic polyurethanes, and homo- and copolymers
of ethylene and propylene; and the preferred thermoset polymers
include the epoxy and urethane resins.
The inorganic layered material which may be used as the reinforcing
agent can be any swellable material which can be intercalated with
an inorganic and an organic intercalant. Representative examples of
inorganic layered materials which may be used in the practice of
the present invention include phyllosilicates such as
montmorillonite, nontronite, beidellite, volkonskoite, hectorite,
saponite, sauconite, magadiite, and kenyaite; vermiculite; and the
like. Other representative examples include illite minerals such as
ledikite; the layered double hydroxides or mixed metal hydroxides
such as Mg.sub.6 Al.sub.3.4(OH).sub.18.8(CO.sub.3)1.7H.sub.2 O (see
W. T. Reichle, J. Catal., 94 (1985), 547), which have positively
charged layers and exchangeable anions in the interlayer spaces;
chlorides such as ReCl.sub.3 and FeOCl, chalcogenides such as
TiS.sub.2, MoS.sub.2, and MoS.sub.3 ; cyanides such as Ni(CN).sub.2
; and oxides such as H.sub.2 Si.sub.2 O.sub.5, V.sub.5 O.sub.13,
HTiNbO.sub.5, Cr0.5V0.5S.sub.2, W0.2V.sub.2.80.sub.7, Cr.sub.3
O.sub.8, MoO.sub.3 (OH).sub.2, VOPO.sub.4 -2H.sub.2 O, CaPO.sub.4
CH.sub.3 ---H.sub.2 O, MnHAsO.sub.4 --H.sub.2 O, Ag.sub.6 Mo.sub.10
O.sub.33, and the like. Other layered materials or multi-layer
aggregates having little or no charge on the surface of the layers
may also be used in this invention provided they can be
intercalated with swelling agents which expand their interlayer
spacing. Mixtures of one or more such materials may also be
employed.
Preferred layered materials are those having charges on the layers
and exchangeable ions such as sodium, potassium, and calcium
cations, which can be exchanged, preferably by ion exchange, with
ions, preferably cations such as ammonium cations, or reactive
organosilane compounds, that cause the multi-lamellar or layered
particles to delaminate or swell. Typically, the negative charge on
the surface of the layered materials is at least about 20
milliequivalents, preferably at least about 50 milliequivalents,
and more preferably from about 50 to about 120 milliequivalents,
per 100 grams of the multilayered material. Particularly preferred
are smectite clay minerals such as montmorillonite, nontronite,
beidellite, volkonskoite, hectorite, saponite, sauconite,
magadiite, and kenyaite, with hectorite and montmorilonite having
from about 20 milliequivalents to about 150 milliequivalents per
100 grams material being more preferred. Most preferred layered
materials are phyllosilicates.
The multilayered material may be intercalated with an inorganic
intercalant and an organic intercalant. The inorganic intercalant
can be an inorganic polymeric substance or an inorganic solid
having a colloidal particle size. Representative polymeric
substances are substances obtained by hydrolyzing a polymerizable
metallic alcoholate such as Si(OR).sub.4, Al(OR).sub.3,
Ge(OR).sub.4, Si(OC).sub.2 H.sub.5).sub.4, Si(OCH.sub.3).sub.4,
Ge(OC.sub.3 H.sub.7), Ge(OC.sub.2 H.sub.5).sub.4 or the like,
either alone or in combination. Representative colloidal sized
particles of an inorganic compound which can be used include the
colloidal sized particles of the hydrolyzed form of SiO.sub.2
(e.g., Si(OH) or silica sol), Sb.sub.2 O.sub.3, Fe.sub.2 O.sub.3,
Al.sub.2 O.sub.3, TiO.sub.2, ZrO.sub.2 and SnO.sub.2 alone or in
any combination. Most preferably, the grain size of the colloidal
inorganic should preferably be in a range of from about 5, more
preferably from about 10, most preferably from about 20, to about
250, more preferably about 120 .ANG..
While it may be possible to intercalate the unmodified form of the
inorganic material between the layers of the multilayered
particulate material, the inorganic intercalant is preferably
modified at its surface by a cationic inorganic compound or a
metallic alcoholate different than the polymerizable metallic
alcoholate. Representative cationic inorganic compounds which may
be used to surface treat the inorganic intercalant are titanium
compounds, zirconium compounds, hafnium compounds, iron compounds,
copper compounds, chromium compounds, nickel compounds, zinc
compounds, aluminum compounds, manganese compounds, phosphorus
compounds, and boron compounds. Metallic chlorides such as
TiCl.sub.4, metallic oxychlorides such as ZrCOCl.sub.2, and nitrate
chloride are preferred. Representative metallic alcoholates which
can be used to the treat the surface of the inorganic intercalant
are Ti(OR).sub.4, Zr(OR).sub.4, PO(OR).sub.3, B(OR).sub.3 and the
like alone or combination, with Ti(OC.sub.3 H.sub.7).sub.4,
Zr(OC.sub.3 H.sub.7).sub.4, PO(OCH.sub.3).sub.3, PO(OC.sub.2
H.sub.5).sub.3, B(OCH.sub.3).sub.3, B(OC.sub.2 H5).sub.3 being
preferred.
The organic intercalant can be any organic material which
displaces, totally or in part, the ions originally on the surface
of the multilayered material. In general, the intercalant contains
a functional group which interacts with the negative charges on the
surface of that material. In addition, the intercalant preferably
also contains a functional group reactive with the matrix polymer
or possesses some property such as cohesive energy, a capacity for
dispersive, polar, or hydrogen-bonding interactions or other
specific interactions, such as acid/base or Lewis-acid/Lewis-base
interactions, to promote the intermingling ("compatibility") of the
matrix polymer and multilayered material.
The organic intercalant can be a water soluble polymer, a reactive
organosilane compound, an onium compound such as an ammonium,
phosphonium or sulfonium salt, an amphoteric surface active agent,
a choline compound, or the like.
Representative examples of water-soluble polymers which can be
employed as the organic intercalant in the practice of this
invention are water soluble polymers of vinyl alcohol (e.g.,
poly(vinyl alcohol); polyalkylene glycols such as polyethylene
glycol; water soluble cellulosics polymers such methyl cellulose
and carboxymethyl cellulose, the polymers of ethylenically
unsaturated carboxylic acids such as poly(acrylic acid), and their
salts, polyvinyl pyrrolidone and the like.
Representative examples of onium compounds include quaternary
ammonium salts (cationic surface active agents) having octadecyl,
hexadecyl, tetradecyl, dodecyl or like moieties; with preferred
quaternary ammonium salts including octadecyl trimethyl ammonium
salt, dioctadecyl dimethyl ammonium salt, hexadecyl trimethyl
ammonium salt, dihexadecyl dimethyl ammonium salt, tetradecyl
trimethyl ammonium salt, ditetradecyl dimethyl ammonium salt and
the like.
Representative examples of the amphoteric surface-active agent
which can be employed in this invention include surfactants having
an aliphatic amine cationic moiety and a carboxyl, sulfate, sulfone
or phosphate as the anionic moiety. Representative examples of
choline compounds include [HOCH.sub.2 CH.sub.2 N(CH.sub.3).sub.3
]+OH --, C.sub.5 H.sub.14 ClNO, C.sub.5 H.sub.14 NOC.sub.4 H.sub.5
O.sub.6, C.sub.5 H.sub.14 NOC.sub.6 H.sub.7 O.sub.7, C.sub.5
H.sub.14 NOC.sub.6 H.sub.12 O.sub.7 and the like.
Representative examples of organosilane compounds include silane
agents of the formula:
where (-) is a covalent bond to the surface of the layered
material, m is 0, 1 or 2; n is 1, 2 or 3 with the proviso that the
sum of m and n is equal to 3; R.sup.1 is a nonhydrolyzable organic
radical (including alkyl, alkoxyalkyl, alkylaryl, arylalkyl,
alkoxyaryl) and is not displaceable during the formation of the
composite; R is the same or different at each occurrence and is an
organic radical which is not hydrolyzable and displaceable during
the formation of the composite which is reactive with the polymer
matrix or at least one monomeric component of the polymer.
Representative R groups include amino, carboxy, acylhalide,
acyloxy, hydroxy, isocyanato ureido, halo, epoxy, epichlorohydryl
and the like. Preferred organosilane intercalants include long
chain branched quaternary ammonium salts and/or suitably
functionalized organosilane compounds, as disclosed in WO 93/11190,
pages 9-21, which are incorporated herein by reference.
Organic materials other than those described can also be employed
as the organic intercalants provided they can be intercalated
between the layers of the multilayered particulate material and
subsequently degraded such as by calcination to at least partially
remove the intercalant and leave gaps between the layers.
In the practice of the present invention, the multilayered
particulate material is intercalated with the inorganic, if
employed, and organic intercalants. While the method of
intercalation is not particularly critical, in one embodiment of
the present invention, prior to intercalating the multilayered
material, it is swollen in an aqueous or organic liquid. Any
aqueous or organic liquid capable of swelling the multilayered
material being intercalated can be employed. By aqueous liquid it
is meant water, including acids and bases as well as some salt
solutions. In addition, solutions of water and one or more
water-miscible organic liquids such as the lower alkyl alcohols,
e.g., methanol and butanol, can be employed. Representative
examples of organic liquids which can be employed include
dimethylformamide, dimethylsulfone, halogenated hydrocarbons, e.g.,
methylene chloride, or a liquid hydrocarbon, preferably having from
about 4 to about 15 carbon atoms, including aromatic and aliphatic
hydrocarbons or mixtures thereof such as heptane, benzene, xylene,
cyclohexane, toluene, mineral oils and liquid paraffins, e.g.,
kerosene and naphtha. The polymerizable inorganic intercalant is
formed as a solution in a suitable solvent such as ethyl alcohol,
isopropyl alcohol and the like and subsequently hydrolyzed,
preferably in the presence of the multilayered material. For
example, a mixture of the multilayered material, swollen in an
appropriate swelling material, and the polymerizable inorganic
intercalant can be contacted with a hydrolyzing agent for the
polymerizable intercalant to form the inorganic polymer. In
general, the hydrolyzation is conducted at a temperature above
about 70.degree. C. Subsequent to partial or complete
polymerization, the organic intercalant can be added. The organic
intercalant reacts upon the hydrolyzed surfaces of the layered
material.
In the event a colloidal inorganic intercalant is used the organic
intercalant can be added to a dispersion of the colloidal inorganic
intercalant. Subsequently, the reaction product of the organic
intercalant with the inorganic intercalant is mixed with the
swollen multilayered material. While the conditions of such
intercalation may vary, in general, it is advantageously conducted
at a temperature of from about 30.degree. C. to about 100.degree.
C., more advantageously from about 60.degree. C. to 70.degree.
C.
Following intercalation, the intercalated multilayered filler can
be dehydrated by conventional means such as centrifugal separation
and then dried. While drying conditions most advantageously
employed will be dependent on the specific intercalant and
multilayered particulate material employed, in general, drying is
conducted at temperatures of at least about 40.degree. C. to about
100.degree. C. and more advantageously at a temperature of about
50.degree. C to about 80.degree. C. by any conventional means such
as a hot air oven. The organic intercalant can then optionally be
calcined such as by heating to about 300.degree. C. to about
600.degree. C., preferably from about 450.degree. C. to about
550.degree. C.
In another embodiment of the present invention, the organic
intercalant can be employed to intercalate the multilayered
particulate material but the inorganic intercalant is not employed.
In this embodiment, the organic intercalant is calcined such as by
heating to about 300.degree. C. to about 600.degree. C., preferably
from about 450.degree. C. to about 550.degree. C.
Following intercalation and, if conducted, calcination, the
intercalant in the multilayered material forms a layer of charge
opposite to the charge on the surface of the layers of the
multilayered particles with the interlayer spacing being dependent
on the intercalants employed and whether the organic intercalant
has been calcined or otherwise partially or totally removed. In
general, the inter-layer spacing (i.e., distance between the faces
of the layers as they are assembled in the intercalated material)
is from about 5 to 600 .ANG. (as determined by X-ray diffraction)
whereas prior to intercalation the interlayer spacing is usually
equal to or less than about 4 .ANG.. This increase in interlayer
spacing permits greater penetration of the polymer matrix into the
filler. Preferably, the interlayer spacing of the intercalated
filler is at least about 8 .ANG., more preferably at least about 12
.ANG. and less than about 100 .ANG., more preferably less than
about 30 .ANG..
Following preparation of the intercalated multilayered material,
the intercalated, multilayered material and matrix polymer are
combined to form the desired composite.
The amount of the intercalated multilayered material most
advantageously incorporated into the polymer matrix is dependent on
a variety of factors including the specific intercalated material
and polymer used to form the composite as well as its desired
properties. Typical amounts can range from about 0.001 to about 90
weight percent of the intercalated, layered material based on the
weight of the total composite. Generally, the composite comprises
at least about 0.1, preferably about 1, more preferably about 2,
and most preferably about 4 weight percent and less than about 60,
preferably about 50, more preferably about 45 and most preferably
about 40 weight percent of the intercalated, layered material based
on the total weight of the composite.
The intercalated, layered material can be dispersed in the
monomer(s) which form the polymer matrix and the monomer(s)
polymerized in situ or alternatively, can be dispersed in the
polymer, in melted or liquid form.
Melt blending is one method for preparing the composites of the
present invention, particularly when forming the composite from a
thermoplastic polymer. Techniques for melt blending of a polymer
with additives of all types are known in the art and can typically
be used in the practice of this invention. Typically, in a melt
blending operation useful in the practice of the present invention,
the polymer is heated to a temperature sufficient to form a polymer
melt and combined with the desired amount of the intercalated,
multilayered material in a suitable mixer, such as an extruder, a
Banbury Mixer, a Brabender mixer, a continuous mixer and the
like.
In the practice of the present invention, the melt blending is
preferably carried out in the absence of air, such as in the
presence of an inert gas, such as argon, neon, nitrogen or the
like. The melt blending operation can be conducted in a batch or
discontinuous fashion but is more preferably conducted in a
continuous fashion in one or more processing zones such as in an
extruder from which air is largely or completely excluded. The
extrusion can be conducted in one zone or step or in a plurality of
reaction zones in series or parallel.
Alternatively, the matrix polymer may be granulated and dry mixed
with the intercalated, multilayered material, and thereafter, the
composition heated in a mixer until the polymer is melted to form a
flowable mixture. This flowable mixture can then be subjected to a
shear in a mixer sufficient to form the desired composite. This
type of mixing and composite preparation is advantageously employed
to prepare composites from both thermoplastic and thermoset
polymers.
A polymer melt containing the intercalated, multilayered
particulate material may also be formed by reactive melt processing
in which the intercalated, multilayered material is initially
dispersed in a liquid or solid monomer or cross-linking agent which
will form or be used to form the polymer matrix of the composite.
This dispersion can be injected into a polymer melt containing one
or more polymers in an extruder or other mixing device. The
injected liquid may result in new polymer or in chain extension,
grafting or even cross-linking of the polymer initially in the
melt.
Methods for preparing a composite using in situ type polymerization
are also known in the art and reference is made thereto for the
purposes of this invention. In applying this technique to the
practice of the present invention, the composite is formed by
mixing monomers and/or oligomers with the intercalated,
multilayered material and subsequently polymerizing the monomer
and/or oligomers to form the polymer matrix of the composite.
The intercalated, multilayered material is advantageously dispersed
under conditions such that at least about 80, preferably at least
about 85, more preferably at least about 90, and most preferably at
least about 95, weight percent of the layers of the intercalated,
multilayered, material delaminate to form individual layers
dispersed in the polymer matrix. These layers may be platelet
particles having two relatively flat or slightly curved opposite
faces where the distance between the faces is relatively small
compared to the size of the faces, or needle-like particles. It is
quite probable that the layers of the filler will not delaminate
completely in the polymer, but will form layers in a coplanar
aggregate. These layers are advantageously sufficiently dispersed
or exfoliated in the matrix polymer such that at least 80 percent
of the layers are in small multiples of less than about 10,
preferably less than about 5, and more preferably less than about
3, of the layers.
The dimensions of the dispersed delaminated layers may vary
greatly, but in the case of particles derived from clay minerals,
the particle faces are roughly hexagonal, circular, elliptical, or
rectangular and exhibit maximum diameters or length from about 50
to about 2,000 .ANG.. As such, the aspect ratio of length/thickness
ranges from about 10 to about 2,000. The aspect ratio which is most
advantageously employed will depend on the desired end-use
properties. The particle faces may also be needle-like.
Optionally, the composites of the present invention may contain
various other additives such as nucleating agents, other fillers,
lubricants, plasticizers, chain extenders, colorants, mold release
agents, antistatic agents, pigments, fire retardants, and the like.
The optional additives and their amounts employed are dependent on
a variety of factors including the desired end-use properties.
The composites of this invention exhibit useful properties. For
example, they may exhibit enhanced yield strength and tensile
modulus, even when exposed to polar media such as water or
methanol; enhanced heat resistance and impact strength; improved
stiffness, wet-melt strength, dimensional stability, and heat
deflection temperature, and decreased moisture absorption,
flammability, and permeability as compared to the same polymers
which contain the same multilayered material which has not
previously been intercalated or where no intercalated material is
employed. Improvements in one or more properties can be obtained
even though small amounts of intercalated multilayered materials
are employed.
The properties of the composites of the present invention may be
further enhanced by post-treatment such as by heat treating or
annealing the composite at an elevated temperature, conventionally
from about 80.degree. C. to about 230.degree. C. Generally, the
annealing temperatures will be more than about 100.degree. C.,
preferably more than about 110.degree. C., and more preferably more
than about 120.degree. C., to less than about 250.degree. C.,
preferably less than about 220.degree. C., and more preferably less
than 180 .degree. C.
The composites of the present invention can be molded by
conventional shaping processes such as melt spinning, casting,
vacuum molding, sheet molding, injection molding and extruding.
Examples of such molded articles include components for technical
equipment, apparatus castings, household equipment, sports
equipment, bottles, containers, components for the electrical and
electronics industries, car components, and fibers. The composites
may also be used for coating articles by means of powder coating
processes or as hot-melt adhesives.
The composite material may be directly molded by injection molding
or heat pressure molding, or mixed with other polymers.
Alternatively, it is also possible to obtain molded products by
performing the in situ polymerization reaction in a mold.
The molding compositions according to the invention are also
suitable for the production of sheets and panels using conventional
processes such as vacuum or hot-pressing. The sheets and panels can
be used to coat materials such as wood, glass, ceramic, metal or
other plastics, and outstanding strengths can be achieved using
conventional adhesion promoters, for example, those based on vinyl
resins. The sheets and panels can also be laminated with other
plastic films such as by coextrusion, the sheets being bonded in
the molten state. The surfaces of the sheets and panels, can be
finished by conventional methods, for example, by lacquering or by
the application of protective films.
The composites of this invention are also useful for fabrication of
extruded films and film laminates, as for example, films for use in
food packaging. Such films can be fabricated using conventional
film extrusion techniques. The films are preferably from about 10
to about 100, more preferably from about 20 to about 100, and most
preferably from about 25 to about 75, microns thick.
* * * * *